/*
 *  VerticalTiltShifPass.cpp
 *
 *  Copyright (c) 2013, satcy, http://satcy.net
 *  All rights reserved. 
 *  
 *  Redistribution and use in source and binary forms, with or without 
 *  modification, are permitted provided that the following conditions are met: 
 *  
 *  * Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer. 
 *  * Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 *  * Neither the name of Neil Mendoza nor the names of its contributors may be used 
 *    to endorse or promote products derived from this software without 
 *    specific prior written permission. 
 *  
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 *  POSSIBILITY OF SUCH DAMAGE. 
 *
 */
#include "VerticalTiltShifPass.h"

namespace itg
{
    VerticalTiltShifPass::VerticalTiltShifPass(const ofVec2f& aspect, bool arb) :
        RenderPass(aspect, arb, "verticaltiltshift"), v(2.0/512.0), r(0.5)
    {
        string fragShaderSrc = STRINGIFY(
            uniform sampler2D tDiffuse;
            uniform float v;
            uniform float r;

            void main() {
                vec2 vUv = gl_TexCoord[0].st;
                vec4 sum = vec4( 0.0 );

                float vv = v * abs( r - vUv.y );

                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 4.0 * vv ) ) * 0.051;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 3.0 * vv ) ) * 0.0918;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 2.0 * vv ) ) * 0.12245;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 1.0 * vv ) ) * 0.1531;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y ) ) * 0.1633;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 1.0 * vv ) ) * 0.1531;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 2.0 * vv ) ) * 0.12245;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 3.0 * vv ) ) * 0.0918;
                sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 4.0 * vv ) ) * 0.051;

                gl_FragColor = sum;
            }
        );
        
        shader.setupShaderFromSource(GL_FRAGMENT_SHADER, fragShaderSrc);
        shader.linkProgram();
#ifdef _ITG_TWEAKABLE
        addParameter("f", this->v, "min=0 max=1");
        addParameter("r", this->r, "min=0 max=1");
#endif
    }
    
    void VerticalTiltShifPass::render(ofFbo& readFbo, ofFbo& writeFbo)
    {
        writeFbo.begin();
        
        shader.begin();
        shader.setUniformTexture("tDiffuse", readFbo.getTexture(), 0);
        shader.setUniform1f("v", v);
        shader.setUniform1f("r", r);
        
        texturedQuad(0, 0, writeFbo.getWidth(), writeFbo.getHeight());
        
        shader.end();
        writeFbo.end();
    }
}
